|Publication number||US4587406 A|
|Application number||US 06/695,970|
|Publication date||May 6, 1986|
|Filing date||Jan 29, 1985|
|Priority date||Feb 17, 1984|
|Also published as||DE3405731C1, EP0154807A1, EP0154807B1|
|Publication number||06695970, 695970, US 4587406 A, US 4587406A, US-A-4587406, US4587406 A, US4587406A|
|Inventors||Wolfram K. Andre|
|Original Assignee||Kurt Wolf & Co. Kg|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (7), Referenced by (27), Classifications (16), Legal Events (5)|
|External Links: USPTO, USPTO Assignment, Espacenet|
1. Field of the Invention
The present invention relates to an apparatus for controlling the cooking process in a cooking vessel placed on an electric heating element, particularly a stovetop burner, having a signal transmitter controlled by the temperature in the cooking vessel, a signal receiver in communication with the signal transmitter by transmitting means for activating a control circuit to adjust the heat output of the heating element, and a switch for turning the device on and off.
2. Description of the Prior Art
Apparatus of this general type are known and are distinguished from one another by the use of different sensor means in the signal transmitters to measure the temperature and of different methods and means for generating and transmitting signals to the signal receiver, as disclosed by German Patent Publication DE-AS No. 21 61 371, German Patent Publication DE-PS No. 25 39 746 and German Patent Publication DE-OS No. 31 29 334, for example.
Since the cooking vessel is not unitary with the heating element, there is the danger in the prior art apparatus that the cooking vessel is placed upon a first heating element while a second heating element is turned on and is heating up. However, the signal receiver fails to register the heating up of the second heating element so that the second heating element continues to receive current and eventually operates at its full capacity heat output while no heat is actually being used for heating a cooking vessel. Since the heat emitted by the second heating element is merely radiating, there is the danger that this heating element will become overloaded and burn out.
A similar situation arises when, during a preset cooking program, the cooking vessel is being removed from the heating element and set aside without turning off the control for the heating element. Impermissible loads may also result when two heating elements having preset cooking programs are activated, and the cooking vessels are accidentally interchanged on the heating elements.
It is an object of this invention to provide an apparatus of the kind referred to above by which any overloading of the heating element or any impermissible overheating of the food in a cooking vessel is prevented during the entire cooking operation in the event that the cooking vessel has inadvertently been placed on the wrong heating element, that a cooking vessel is removed from the heating element during the cooking operation while maintaining the control for the heating element in the ON position, or that several cooking vessels have been interchanged and placed on heating elements having different or like programs.
This is accomplished according to the present invention in that a periodic monitoring of the switch position of the control circuit of the heating element is initiated as the ON switch is actuated, that at the beginning of each monitoring cycle it is determined whether the heating element has been set by the control circuit to a full capacity or reduced heat output, that in the case of full capacity heat output the temperature value supplied by the signal receiver at the beginning of a monitoring cycle is stored, that at the end of the monitoring cycle this stored temperature value is compared with the temperature value supplied by the signal receiver at the end of the monitoring cycle, and that if the comparison fails to show any change in temperature during the course of the monitoring cycle, then the control circuit of the heating element is turned off at the end of the monitoring cycle.
If, according to this arrangement, the cooking vessel is placed on the wrong heating element during the heating phase of a particular heat output setting, the control circuit of the heating element will be deactivated after the first monitoring cycle because no temperature rise was measured at the end of the monitoring cycle.
When the cooking vessel is removed from a hot heating element during the cooking operation and is set aside, the ensuing cooling off of the cooking vessel causes the control circuit of the heating element to be gradually adjusted to reach its full heat potential so that during the next monitoring cycle the control circuit of the heating element is deactivated because the temperature no longer rises but, instead, falls.
If two cooking vessels are pre-programmed, one for Hold Warm on a first heating element and the other for Quick Cook on a second heating element, for example, but the cooking vessels are accidentally interchanged and are placed on the wrong burners, the first heating element following the heat-up phase will nevertheless move into the regular phase for Hold Warm. The second heating element, following the initial heat-up phase, continues to operate at its top output. The first cooking vessel placed on the second heating element signals "too hot" for the regular phase and, consequently, the control circuit of the first heating element is deactivated. This has the result that no heat will be supplied to the second cooking vessel placed on the first heating element, and this initiates the controlling operation since the temperature in the second cooking vessel fails to rise, and the control circuit for the second heating element is deactivated. Consequently, the first cooking vessel on the second heating element also cools off which causes the control circuit of the first heating element to be activated. The temperature in the first cooking vessel fails to rise and the control circuit for the first heating element is deactivated. Thus, both heating elements are in the OFF position.
Even if both heating elements are pre-programmed with the same program, both heating elements remain in the OFF position when the cooking vessels are interchanged and placed on the wrong heating element. Since complete symmetry as to quantity of water and quantity of food in two cooking vessels is nearly impossible to reach, at any one point in time, the first cooking vessel will have a temperature different from the temperature in the second cooking vessel. If the second cooking vessel is too hot, the temperature will be turned down by the control circuit of the first heating element. Consequently, the full capacity heat output setting is switched on for the second cooking vessel because the second cooking vessel was placed on the first heating element and is cooling off. Further operation to achieve complete deactivation of the control circuits of both heating elements is the same as in the case of interchanged, differently pre-programmed cooking vessels.
Thus, all conceivable sources of error are monitored and in each case any overloading of the heating elements is prevented by timely deactivation of the control circuits, so that food in the cooking vessels is never overheated.
If, according to one embodiment, the control circuit is in the form of a cyclic control arrangement which operates at predetermined switching cycles and at the beginning of each switching cycle presets the period for the next switching cycle, the control signal of the cyclic control circuit indicates activation of the heating element for the entire switching cycle at the beginning of the switch cycle, thereby supplying the requisite signal for the monitoring operation.
Signals for monitoring and deactivating the control circuit of the heating element are derived, according to one embodiment, in that a central monitor clock is provided which is adapted to be activated simultaneously with the ON switch, that this cyclically operating monitor clock scans the control circuit at the beginning of each monitoring cycle for its switch position, that the signal receiver is activated to store in memories the temperature values corresponding to actual temperatures, that at the end of each cycle the differential of the temperature values stored in the memories is obtained by means of a differentiating circuit, and that when a zero or negative temperature differential is measured at the end of the monitoring cycle, a switch is energized which turns off the power supplied to the system by way of the ON switch.
Turning off the power may be accomplished in a very simple manner by the switch causing a contact to open the power supply line to the control circuit of the heating element.
It has been found useful that the contact is adapted to deenergize also the power supply to the monitor clock, the memories, the signal transmitter and the signal receiver, so that the entire system is left without current or voltage.
According to another embodiment, the controlling operation does not interfere with convenient handling of the cooking vessels if the signal receiver, the memories, the differentiating circuit and the monitor clock are associated with the heating element including the control circuit, the signal transmitter is associated with the cooking vessel, and the signal transmitter is in communication with the signal receiver by wireless transmission means.
The device may be further simplified if the monitoring cycle is equal to, or a multiple of, the switching cycle of the control circuit and is synchronized with it.
The invention will be further described with reference to an embodiment represented schematically in the FIGURE by a block diagram.
Sensor means provided at or within the cooking vessel may comprise a temperature sensing probe, for example, which functions as signal transmitter TF and supplies signals over a wireless transmitting means Ue to signal receiver TE, the signals corresponding to the measured temperature. Signal receiver TE is associated with heating element HE having control circuit St. The output of signal receiver TE are supplied in digital form and correspond to the measured temperatures.
Switch S serves to activate and deactivate the entire system. Switch S is connected to the power supply line leading from plug P supplying alternating current voltage to control circuit St and heating element HE. If control circuit St is in the form of a cyclic control circuit, heat output is adjusted depending upon the temperature value supplied by signal receiver TE. To this end, the control circuit, at the beginning of a switch cycle determines the period of time during which the heating element is activated in the next switch cycle. During the activated ON time, the heating element operates at full capacity output. At the beginning of a switch cycle, a signal may be supplied by control circuit St to indicate that heating element HE will operate at full capacity for the duration of the next switch cycle. This particular feature is utilized for the monitoring operation according to the present invention.
Simultaneously with the actuation of switch S, monitor clock Tu is energized. At the beginning of each monitoring cycle tz, clock Tu receives information from control circuit St as to whether the heating element will be set at its full capacity position during the next switching cycle. Upon a positive response, monitor clock Tu causes temperature value Ta supplied to signal receiver TE at this point in time ta to be stored in memory SPa. With a negative response, no further switching action occurs, and the same determination is made at the beginning of the next monitoring cycle. It will be appreciated that the apparatus is further simplified if the monitoring cycle is made to coincide with the switching cycle of control circuit St and is synchronized with it. Temperature value Ta is supplied at the beginning of the monitoring cycle by signal receiver TE and is stored in memory SPa. At the end of the monitoring cycle, temperature value Te, measured at this time te, is stored in memory SPe. Differentiating circuit D ascertains whether zero differential, or a negative differential, ne, is measured, i.e., whether during the previous monitoring cycle the temperature has remained the same or whether it has dropped. A finding of negative or zero differential is interpreted as an indication that the cooking vessel is not correctly associated with respect to heating element HE. Thereupon, switch means A is energized to open the power supply line by means of the normally closed contact of changeover contact a, so that control circuit St and heating element HE are deenergized. Likewise, monitor clock Tu, memories SPa and SPe, signal receiver TE and differentiating circuit D, all associated with heating element HE, are without current.
Signal transmitter TF associated with the cooking vessel, has a power source of its own, such as a battery, because transmitting device Ue is preferably wireless.
As switch means A is energized, the holding circuit for switch means A comprising the contact of changeover switch a and ON switch S is still closed. Heating element HE is maintained in the OFF position until switch S has been deactivated. Renewed turning on of switch S initiates a new cycle of the monitoring operation.
Each time it is determined that for the next switching cycle of control circuit St heating element HE is set to full heating capacity, the temperature values Ta and Te are stored at the beginning and the end, respectively, of the monitoring cycle and the differential is obtained at the end of the monitoring cycle. The type of error responsible for the failure of the temperature to rise is immaterial. Any time the temperature fails to be adjusted, or even decreases, during the course of a monitoring cycle, there is a malfunction in the system and control circuit St of heating element HE is deactivated.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4403302 *||Oct 30, 1980||Sep 6, 1983||Essex Group Inc.||Automatic resetting of control system for loss of time reference|
|US4433232 *||May 29, 1981||Feb 21, 1984||Hitachi Heating Appliances Co., Ltd.||Heating apparatus|
|US4461951 *||Aug 16, 1982||Jul 24, 1984||E. I. Du Pont De Nemours And Company||Method of monitoring the temperature of a sterile docking cutting means|
|US4499368 *||Mar 5, 1984||Feb 12, 1985||General Electric Company||Utensil removal detection system for cooking appliance|
|DE2161371A1 *||Dec 10, 1971||Jun 14, 1973||Karl Fischer||Regelgeraet|
|DE2539746A1 *||Sep 6, 1975||Mar 17, 1977||Karl Fischer||Regulator for electric cooking plates - has temp. sensitive resistor in blocking oscillator responding to condensed vapour|
|DE3129334A1 *||Jul 24, 1981||Apr 1, 1982||Sharp Kk||"vorrichtung zur steuerung eines kochgeraetes"|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4803344 *||Dec 9, 1987||Feb 7, 1989||Fissler Gmbh||Apparatus and process for controlling the simmering or cooking time in a cooking vessel|
|US4839503 *||Dec 9, 1987||Jun 13, 1989||Fissler Gmbh||Controlling the simmering or cooking time in a cooking vessel|
|US4962299 *||Jun 19, 1989||Oct 9, 1990||Seb, S.A.||Method and apparatus for the thermal control of a heating device|
|US5099108 *||Jan 9, 1990||Mar 24, 1992||Paloma Kogyo Kabushiki Kaisha||Electric control system for liquid heating apparatus of the pulse combustion type|
|US5324917 *||Sep 14, 1990||Jun 28, 1994||Compagnie Europeenne Pour L'equipement Menager-Cepem||Device and method for regulation the temperature and/or power of a cooking apparatus|
|US5442157 *||Nov 6, 1992||Aug 15, 1995||Water Heater Innovations, Inc.||Electronic temperature controller for water heaters|
|US5945017 *||Aug 6, 1997||Aug 31, 1999||Cheng; Yu-Tarng||Fire safety device for stove-top burner|
|US6320169||Sep 6, 2000||Nov 20, 2001||Thermal Solutions, Inc.||Method and apparatus for magnetic induction heating using radio frequency identification of object to be heated|
|US6818867||Dec 9, 2003||Nov 16, 2004||Braun Gmbh||Method for heating liquid in an electric kettle|
|US6953919||Jan 31, 2003||Oct 11, 2005||Thermal Solutions, Inc.||RFID-controlled smart range and method of cooking and heating|
|US7080593 *||Oct 2, 2003||Jul 25, 2006||David Frankel||Controlled cooking system|
|US7573005||Mar 18, 2005||Aug 11, 2009||Thermal Solutions, Inc.||Boil detection method and computer program|
|US8217321 *||May 28, 2009||Jul 10, 2012||E.G.O. Elektro-Geraetebau Gmbh||Method for generating, processing and analysing a signal correlated to temperature and corresponding device|
|US8598497||Mar 29, 2011||Dec 3, 2013||Bose Corporation||Cooking temperature and power control|
|US8754351||Nov 30, 2011||Jun 17, 2014||Bose Corporation||Induction cooking|
|US9006622||Nov 30, 2011||Apr 14, 2015||Bose Corporation||Induction cooking|
|US9131537||Dec 1, 2014||Sep 8, 2015||Boise Corporation||Cooking temperature and power control|
|US9237829 *||May 10, 2012||Jan 19, 2016||Electrodomesticos Taurus, Sl||Cooking hob with rotary driving means and cooking vessel usable with said hob|
|US20040149729 *||Dec 9, 2003||Aug 5, 2004||Frank Kressmann||Method for heating liquid in an electric kettle|
|US20040149736 *||Jan 31, 2003||Aug 5, 2004||Thermal Solutions, Inc.||RFID-controlled smart induction range and method of cooking and heating|
|US20050247696 *||Mar 18, 2005||Nov 10, 2005||Clothier Brian L||Boil detection method and computer program|
|US20090294433 *||May 28, 2009||Dec 3, 2009||E.G.O. Elektro-Geraetebau Gmbh||Method for Generating, Processing and Analysing A Signal Correlated to Temperature and Corresponding Device|
|US20140203010 *||May 10, 2012||Jul 24, 2014||Electrodómestics Taurus S.L.||Cooking hob with rotary driving means and cooking vessel usable with said hob|
|USRE42513||Jan 18, 2006||Jul 5, 2011||Hr Technology, Inc.||RFID—controlled smart range and method of cooking and heating|
|EP1588586A2 *||Jan 23, 2004||Oct 26, 2005||Thermal Solutions, Inc.||Rfid-controlled smart induction range and method of cooking and heating|
|WO2004071131A2||Jan 23, 2004||Aug 19, 2004||Thermal Solutions, Inc.||Rfid-controlled smart induction range and method of cooking and heating|
|WO2011157865A1||Apr 14, 2011||Dec 22, 2011||Electrodomésticos Taurus, Sl||Motor-driven cooktop and cooking container that can be used on said cooktop|
|U.S. Classification||219/497, 219/448.11, 219/518, 219/508, 340/589, 99/328, 219/492, 99/332|
|International Classification||A47J27/62, H05B3/00, A47J27/00, G05D23/19|
|Cooperative Classification||A47J27/62, G05D23/1905|
|European Classification||G05D23/19B4, A47J27/62|
|Dec 26, 1985||AS||Assignment|
Owner name: KURT WOLF & CO. KG, LANGWIESENWEG 67/71, D-7547 WI
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ANDRE, WOLFRAM K.;REEL/FRAME:004491/0154
Effective date: 19850501
|Aug 17, 1988||AS||Assignment|
Owner name: FISSLER GMBH, MAINZER STRASSE 34, D-6580 IDAR-OBER
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:KURT WOLF & CO. KG., A LIMITED PARTNERSHIP OF GERMANY;REEL/FRAME:004941/0192
Effective date: 19880809
Owner name: FISSLER GMBH, A CO. LIMITED LIABILITY OF GERMANY,G
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KURT WOLF & CO. KG., A LIMITED PARTNERSHIP OF GERMANY;REEL/FRAME:004941/0192
Effective date: 19880809
|Jun 19, 1989||FPAY||Fee payment|
Year of fee payment: 4
|Nov 4, 1993||FPAY||Fee payment|
Year of fee payment: 8
|Sep 29, 1997||FPAY||Fee payment|
Year of fee payment: 12